Sunfish Rudders

Can anyone tell me what the critical component measurements are for knowing if a rudder will work on a Sunfish? There is a rudder available for sale about an hour and 45 minutes from me, and it looks a whole lot like a sunfish rudder and tiller. The seller was nice enough to take very good measured photos of it. I THINK the pin that attaches in the gudgeon is a little less than half an inch shorter than the one on the rudder that came with my derelict sunfish project. I thought maybe it...

Sunfish Rudders